Modal Identification of Over-Damped Structural Systems Using Extended Ibrahim Time-Domain Method

摘要

In the previous study, the conventional Ibrahim time-domain method (ITD) using free-decay responses of structures has been extensively used in the modal-identification analysis, however, which is only applicable to identify the modal parameters of an under-damped structure. In the present paper, we propose a theoretical modification for ITD method, and extend the ITD method for modal identification of over-damped structural systems. The eigenvectors of the system matrix used in extended ITD method corresponding to the vibrating modes of a structural system in pair are sorted through the assurance index proposed in this paper based on the theory of structural dynamics. Numerical simulations confirm the validity of the proposed method for modal identification of over-damped structural systems.